Catalyzed anionic redox in sulfide electrolytes for high-energy all-solid-state organic batteries

The electrochemical energy-storage community continues to seek sustainable, high-energy-density, metal-free cathodes that can replace conventional transition-metal-based systems. Organic electrode materials (OEMs) offer promising advantages, including structural tunability, low cost, and environmental compatibility. However, their performance in liquid electrolytes is limited by severe dissolution. All-solid-state batteries (ASSBs) have recently emerged as a promising pathway to mitigate this issue. However, interfacial reactions between OEMs and inorganic solid electrolytes often suppress reversible capacity and cycling stability. This study shows that when deliberately controlled, these interfacial reactions can instead be leveraged to catalyze reversible S 2− anionic redox in sulfide solid electrolytes. By systematically tuning both the redox potential of OEMs and the local sulfur bonding environments across a series of sulfide electrolytes, we identify an optimal composition in which OEMs initiate an outer-sphere oxidation pathway that circumvents the intrinsically sluggish electrochemical S 2− redox process. This catalytic mechanism substantially enhances reversible capacity. In optimized ASSBs, the perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA)/Li 6 PS 5 Cl system achieves an electrode-level energy density of 477 Wh kg −1 , delivers stable cycling for over 2,000 cycles, and maintains high areal capacities of 5.2 mAh cm −2 . More broadly, this work establishes a conceptual shift that interfacial reactivity in ASSBs need not be merely mitigated but can be strategically exploited. The design principles introduced here highlight how catalytic interfacial phenomena may be purposefully integrated to advance next-generation sustainable ASSBs with elevated energy density. • Catalyzed S 2− anionic redox unlocks high-capacity all-solid-state batteries • Optimal OEM-electrolyte pairing enables 477 Wh kg −1 energy density • Interfacial reactions become beneficial via controlled outer-sphere redox • S 2− redox requires moderate OEM potential and low cation–S bond covalency Catalyzed S 2− anionic redox unlocks high-capacity all-solid-state batteries Optimal OEM-electrolyte pairing enables 477 Wh kg −1 energy density Interfacial reactions become beneficial via controlled outer-sphere redox S 2− redox requires moderate OEM potential and low cation–S bond covalency All-solid-state batteries (ASSBs) can prevent the dissolution of sustainable organic electrode materials (OEMs) in liquid electrolytes, but their practical implementation is limited by the low energy density arising from interfacial reactions between OEMs and solid electrolytes (SEs). Here, we show that controlled interfacial chemistry between OEMs and sulfide SEs can instead activate reversible S 2− anionic redox, enabling an electrode-level energy density of 477 Wh kg −1 and stable cycling for over 2,000 cycles at room temperature. Mechanistic analysis identifies two key criteria for effective OEM-catalyzed S 2− anionic redox: (1) a moderate OEM electrode potential sufficient to oxidize S 2− without over-oxidation and (2) low cation–S 2− bond covalency, localizing electron density on S atoms to enhance redox activity. Our findings challenge the prevailing notion that a chemically inert cathode-electrolyte interface is essential for excellent electrochemical performance and offer a pathway for next-generation sustainable ASSBs with high energy density.